The business end of an excavator is a chain of parts that wear together: tooth, adapter, lip, pin, bushing, link, and the cylinder that moves all of it. Owners usually replace the item that fell off. The money is saved by replacing the item that is about to cause the next failure, which is rarely the same one. This is how we look at a bucket and its linkage before quoting.
The wear chain
- Tooth and adapter. The tooth wears, the adapter seats wear with it, and once the seat is worn the new tooth will not seat properly — it will loosen and then be lost. A lost tooth usually means a worn adapter, not a bad tooth.
- Lip and side cutters. The lip the adapters weld or bolt to wears and cracks. Rebuilding a lip is a fabrication job, not a parts job, and it is worth doing before the adapters stop seating.
- Pins and bushings. Every pivot wears. As clearance grows, the geometry of the whole linkage changes, and the cylinder starts working at angles it was not designed for.
- Link and lever. The H-link and the connecting links take the reaction loads. Cracks here start at the welds and at the pin bosses.
- Bucket cylinder. The cylinder takes the shock of every bite. A worn bucket cylinder seal is often the last symptom of a chain that has been sloppy for a thousand hours.
What to measure, not guess
| Item | How to judge it | Replace when |
|---|---|---|
| Tooth | Compare length and point profile with a new one | Well before the adapter is exposed — a tooth that is gone is already damaging its seat |
| Adapter | Fit a new tooth; it should seat tight with no rock | The new tooth rocks, or the seat is visibly waisted |
| Pin and bushing | Measure the clearance; pry the joint and watch the movement | Movement is visible, or the pin has turned in the boss |
| Link | Look for cracks at welds and elongated pin holes | Any crack, or a hole that is no longer round |
| Lip | Thickness and crack check along the full width | Cracks propagating, or adapter seats that no longer hold |
Three decisions that change the bill
- Replace pins and bushings together. A new pin in a worn bushing lasts a fraction of its life, and a new bushing around a worn pin is no better. They are sold as a pair for a reason.
- Match the tooth system to the ground, not to the price. A heavy penetration tooth in soft clay digs slower and loads the linkage more; a light tooth in shot rock disappears in a day. The wrong tooth costs more in fuel and linkage wear than it saves in steel.
- Fix the clearance before it changes the geometry. A sloppy pivot puts side load on the cylinder rod. Rod damage is an order of magnitude more expensive than the bushing that caused it.
How the machine's work should drive the choice
- General trenching in mixed ground: standard tooth, standard adapter, replace on a visible wear limit.
- Abrasive sand and gravel: expect fast adapter and lip wear; inspect the seats every time you change teeth.
- Rock and demolition: penetration teeth, heavier adapters, and a much shorter inspection interval on the links.
- Ditching and grading: the lip and side cutters wear more than the teeth; a wide, clean lip matters more than a sharp point.
Before you order
Ground engaging parts are sized to the machine class and to the bucket, and the tooth system on a Kobelco bucket is not universal across generations or across buckets from different makers. Send the machine model and serial number, the bucket width and type if you know it, and photographs of the tooth seat, the pin boss and any number cast into the adapter or the link. We will match what is actually on the machine rather than what a catalogue suggests for the model. Our team quotes from 3,000+ part types held on the shelf in Guangzhou, with 100,000+ part numbers available to order, and every line states genuine, OEM or aftermarket — we are an independent supplier of Kobelco parts and not an authorized Kobelco dealer.